Appliance for delivering plastic substances under high pressure



Nov. 4, 1952 BANZ 2,616,130

APPLIANCE FOR DELIVERING PLASTIC SUBSTANCES UNDER HIGH PRESSURE FiledSept. 7, 1949 l N V ENTOR'.

FRIEDRICH BA ATTORN Ey Patented Nov. 4, 1 952 OFFICE APPLIANCE FORDELIVERING PL ASTIC SUBSTANCES UNDER HIGH PRESSURE Friedrich Banz,Erlenbach, near Zurich,

Switzerland Application September 7, 1949, Serial No. 114,336 InSwitzerland June 16, 1949 The present invention relates to an appliancefor delivering plastic" substances under high pressure. I

Known appliances for delivering plastic substances have, for taking theplastic substance, two pressure chambers which are alternately filledand alternately emptied through a common mouthpiece. While the substanceis being pressed out of one pressure chamber and being filled into theother, the connection between the two chambers through the commonejection mouthpiece is to be broken, the member which effects thisconnection or this interruption having to keep tight against the highpressing pressure and being therefore complicated to construct andcontrol.

The appliance according to the invention has two pistons which arearranged concentrically to each other and are axially displaceableindependent of each other in a pressure chamber connected to theejection mouthpiece for the substance and to a storage container for thesubstance, an annular member coupled to the inner piston being arrangedin this chamber axially displaceable along the wall of the chamber.

One example of execution according to the invention is illustrated inthe accompanying drawing.

According to this drawing, in a pressure chamber I with ejectionmouthpiece 2 for the plastic substance, two pistons 3 and 4 aredisplaceably arranged, which are concentric to each other and movableindependent of each other. The inner piston 3 has a piston plate 6displaceable in the pressure cylinder 5, whilst the outer hollow piston4 is connected to the piston plate 8 displaceable in the pressurecylinder 1.

In the pressure chamber I an annular member 9 is arranged displaceablealong the wall of the pressure chamber; the bore in this member is lessthan the diameter of the inner piston 3, and the member is held betweenthe end of the piston 3 and four ribs I0 extending radially out from thepiston. This annular member 9 is thus coupled to the piston 3 and moveswith it, whereby it is movable between the end of the piston and theribs I0 serving as displacing means.

On the pressure chamber I a funnel-shaped storage container II is fittedfor holding the plastic mass to be pressed; the container I I is inconnection with the pressure chamber I through an opening I2, thisopening being controlled by the piston 4.

Pipes I3 to I6 allow of a pressure medium, for instance oil, beingadmitted and/or led away for 3 Claims. (CI. 18-30) moving the pistons.As can be seen from the following description of the method of workingof the appliance, this admission and removal of the pressure medium iscontrolled in a certain rhythm by means not shown in the drawing.

.Starting with the parts in the position illustrated, the piston 3 movestowards the ejection opening 2 and thereby carries the annular member 9along with it,. so thatthe substances in front of the piston and member9 is compressed and ejected. At the same time the space behind theannular member 9 and round the piston 3 fills with plastic substancefrom the storage container II. The following piston 4 compresses thissubstance, pressing out any air present in it, up to the pressureprevailing in front of the piston 3. In addition, piston 4 closes theopening I2 when passingalong, and the piston 3 commences its returnstroke. The annular member 9 then comes to lie against the ribs I0, andthe substance delivered by the piston 4 flows through the bore of thering past the ribs Ill into the end of the pressure chamber I where theejection mouthpiece 2 islocated. When the pistons 3 and 4 havesimultaneously arrived respectively at the rear end and at the front endof their strokes, their directions of motion are reversed. The annularmember 9 comes to lie against the tapered front end of the piston 3, andthe plastic substance in front of the ring 9 and the piston is pressedout through the ejection mouthpiece, after which the described cyclestarts again.

What I claim is:

1. In a device for delivering plastic substances under pressure, incombination, an inner piston and an outer piston in coaxial arrangementto each other, a common pressure chamber in which said pistons areaxially movable, an ejection mouthpiece at one end of said pressurechamber, a storage container connected to said chamber at a pointrearwardly of the position of furthest rearward movement of said innerpiston, spaced abutments on the forward end of the inner piston, saidend being of reduced diameter adjacent said abutments, and an annularmember having a bore in which is received the said end of reduceddiameter and having an external diameter corresponding to the diameterof said chamber, said annular member being slidable along the inner wallof said chamber and movable between said spaced abutments and the mainportion of the said inner piston, said end of said inner piston beingmovable into closin relation with the bore in the annular member on theforward stroke t e eoi.

2. In a device for delivering plastic substances under pressure incombination, an inner piston and an outer piston in coaxial arrangementto each other, a common pressure chamber in which said pistons areaxially movable, an ejection mouthpiece at one end of said pressurechamber," a storage container connected to said chamber at a pointrearwardly of the position of furthest rearward movement of said innerpiston,

the inner piston having a tapered end, ribs on said tapered end, anannular member slidable along the inner wall of said chamber and movableover the tapered portion of said inner piston between said ribs and themain portion-of the piston and having an external diameter correspondingto the diameter of said chamber, the bore in said annular memberbeing-ofless diameter than the outer diameter of said inner piston, andsaid tapered end of said inner piston being movable into closingrelation with the bore in' the annular member on thevforward-strokethereof.

3. In a device for delivering plastic substances under pressure incombination, an inner piston and an outer piston in coaxial arrangementto each other, a common pressure chamber in which said pistons areaxially movable, an ejection mouthpiece at one end of said pressurechamber, a storage container connected to said chamber, the inner pistonhaving a tapered end, ribs on said tapered end, an annular memberslidable along the inner wall of said chamber and movable over thetapered portion of said inner piston between said ribs and the mainportion of the piston and having an external diameter corresponding tothe diameter of said chamber, the bore in said annular member being ofless diameter than' the'souterzdiameter of said inner piston, and acommunication port between said storage container and the pressurechamber at a; point rearwardly of the position of furthest rearwardmovement of said inner piston and controlled by. the outer piston, thetapered end of said inner piston being movable into closingrelationwithhtheebore in the annular member on theforward strokethereof.

FRIEDRICH BANZ.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 777,870 Vel1ino.'.. .v Dec. 20,1904 856,026 Brown-et a1; June 4, 1907 2,454,661 Lester et a1 Nov. 23,1948 FOREIGN PATENTS Number Country Date 501,277 Great Britain Feb. 21,1939

